Electrical-fuse block.



A. A. MOFFITT & G. E. ANDREWS. ELECTRICAL FUSE BLOCK.

APPLICATION FILED JULY 23. 1909.

946,251, Patented Jan. 11,1910.

' *Figi am y Afro/mers ANDREW ALEXANDER MOFFITT AND GEORGE EARL ANDREWS,0F PROVIDENCE;

RHODE ISLAND.

, ELECTRICAL-FUSE BLOCK.

Specification of Letters Patent. Patented Jan. 11, 1910.

Application filed July 23, 1909.- Serial No. 509,221.

To all who/m 'it may concern:

Be it known that we, ANDREW A.. MOF- rrr'r and GEORGE E. ANDREWS,citizens of the United States, and residents of Providence, in thecountyA of Providence and ,State of Rhode Island, have invented a newand Improved Electrical-F use Block, of which rthe following is a full.clear, and eX- act description.

Our invention relates to fuse blocks and fuses to be used in connectiontherewith, our more particular' purpose being to so adjust the fusesrelatively to the fuse block, as to prevent the 'insertion 'in aparticular block of a fuse built for greater amperage than one intendedto be inserted in said block.

More particularly stated, our invention comprehends a fuse block soconstructed that the insertion of a fuse of too great amperage isimpossible, owing to the fact that the fuse to be kept out of the blockis a misfit, being suitable for some other block.

Reference is to be khad to the accompanying drawings forming cation, inwhich similar characters of reference indicate corresponding parts inall the figures.

Figure l is a central longitudinal section through our improved blockand the fuse used in connection with it, the parts being in their normalposition and the fuse ready for electric action. Fig. 2 is a verticalsection through the fuse block, approximately on the line 2--2 of F ig.l, looking in the direction of the arrow, and showing the clip forming apart of the block and engaging a boss mounted upon the fuse, saidbossbeing of proper size to 'tit into said clip; Fig. 3 is a verticalsection, approximately on the line 3-3 of Fig. l, looking in thedirection of the arrow, and showing another clip for holding the fuse;and Fig. fl ,is a fragmentary vertical section showing a fuse block,being of greater amperage than is intended for said block.

The application for which this invention is more particularly designedis upon the structures generally known as cartridge fuses. The principalobject which it has 1n viewis to prevent the introduction, between lthefuse terminals of the line, of a fuse having a larger ampere Capacitythan is designed for the line. Heretofore where fuses a part of thisspeci-v vsue-h as the screw plug, ordinary cartridge or the open wiretype have been used, 1t has been customary 1n making temporaryinstallations, requiring a larger capacity than l is supplied by theblock used in the original installation, to remove the original fuse andsubstitute `therefor one of.- larger, and in many instances, of adangerously large carrying capacity. This has resulted in permitting aload to be introduced on the wires, which has taxed, and in manyinstances, broken down the insulation by heat, resulting often inproducing a dangerous re.

By means of the present invention it becomes impossible to supply theline with a fuse of a larger ampere capacity than that designed. And, ifit be desired to vary the shapes of the selective terminals with whichthe fuses are provided, itmay beso arranged that the exact fuse must beused in all fuse blocks constructed in accordance with the presentinvent-ion.

Mounted upon a wall, 5, or other support, is a base 4- of porcelain orsimilar material, secured in position by screws 6. The base 4 isprovided with a compartment T having generally a cylindrical form. Thebase 4 is further. provided with recesses 8. 9 which merge into thecompartment T and are located at the ends of the base. Mounted withinthe recess S is a lug 10 secured in position by screws 11 which serve asbinding posts and are adapted to grip a wire '19, asindicated in Fig.1,'a portion l2 of this wire being bare for facilitating this object.

Integral with the lug l() and depending therefrom are metallic springs13 of arcuate form, these springs and the lug together constituting aclip. At the opposite and of the base a lug 1l is mounted within gherecess 9 and is engaged by screws l5 corresponding to the screws 11. Thelug ll is provided with metal springs 1G of arcuate form, these springsbeing somewhat similar to the springs 13 but having a more abruptcurvature, thus approximating a cylinder of comparatively smalldiameter.

AtI 17 is an annular support made of insulating material and mountedrigidly with-` in the compartment 7. A fuse 1S is provided withcylindrical contact members 19, 20 and with a knob 21, the latterserving as a handle. The fuse is also provided with a boss 22 serving asa gage, and also, to some extent, as a limiting stop, That is to say,for each pair of contact springs 16 the fuses to match the same are eachprovided with a boss 22 of proper diameter to iit into the springs 16.

At 18EL (see Fig. 4) is shown a fuse provided with an annular contactmember 20u, and also With a boss 22, the diameter ,of this boss beinggreater than that of the boss 22 shown in Fig. 1, but other parts of thefuse bein'gvexactly like those shown in said ligure.

As indicated in Fig. 4, when the fuse provided With the boss 222L ispartially inserted into the compartment 7, the boss 222L is un able toextend through the annular shoulder 17, or intermediate the contactsprings 16. Hence, the fuse 18a can not be insertedso as to have anyelectrical effect Whatever, because no metallic portion of this fuse canbe brought into engagement With the springs 16.

From the above description, it Will read-y ily be seenvhoW the inventionoperates in practice. Suppose, for instance, that the base shovvn inFig. 1 is intended for use in connection with currents of, say, fiveamperes, and that the fuse 18 is a live ampere fuse. In this event thediameter of the boss 22 is so apportioned that this boss'can fit intothe springs 16. The operator, then, by grasping the handle 21 can insertthe fuse endivise, so that the boss 22 extends through the support 17and engages the springs 16, as indicated in Fig. 1, the fuse being nowproperly Yinserted and ready for action. Suppose, however, that theoperator, through ignorance or by accident, attempts to insert the fuse18a (Fig. 4), this fuse being able to carry, say, ten amperes. The boss22, in this fuse of greater amperage, is made of greater diameter, asindicated in Fig. 4. Hence, the boss 22a lodges against the support 17and is unable to extend terethrougi into engagement with the contactsprings 16. Moreover, the support 17, being of insulating material,prevents any possibility of the boss 22a even touching any metallicmember which might otherwise comph Le a circuit momentarily.

In practice, While a considerable variety of fuses may be employed, theyare all alike as to external appearance, with the exception that theboss 22 in one fuse hasa greater diameter than in another. Similarly ifthere be a number oit bases 4 they may be all alike in generalappearance, with the exception that in one the contact springs 16 havesuch curvature as would correspond to' a circle of smaller diameter thanwould be the case with l* the corresponding springs in another base.

The operation of our device is as follows: The'fuse block as a Whole isused a good deall like any other fuse block, so long as the proper fusesare employed with it. The operator grasps one of the fuses by the handle21 and inserts the fuse endivise into the compartment 7. Ifthe fuse 4iseasily inserted, soy that the handle 21 takes up the position indicatedin Fig. 1, the fuse is simply left in position. It it happens, however,that the boss 22 of this fuse 1s too small for the particular springs16, no electric circuit is completed, and the fuse should be Withdrawnand replaced by another. l If, on the contrary, the fuse sought to beinserted does not move into its proper pos'tion as indicated by theextent to which the handle 21 pro trudes, the operator is therebyapprised that the fuse he is attempting to insert is one of too greatamperage. Moreover, the operatorl can tell by the sense of feeling,Whether the fuse he is .attempting to fit into position is the oneintended for the particular block. It the boss 22 does not touch thesupport 17 lor the springs 16 as is always the case when the fuse is oftoo small amperage, the operator detects this fact by the ease withWhich the fuse is inserted intoposition, or by the fact that the fusedoes not move far enough into the compartment to make a proper lit.

By aid of the device above described, the possibility of using a fuse ofimproper amperage, and particularly of amperage too great, is eectvelyavoided, and the safety of electrical apparatus thereby enhanced to thatextent. It will also be noted that in the fuses above described thecontact members 19, 20 are of the usual cylindrical form, and that theyadaptthe fuse for insertion in an ordinary fuse block, as Well as in thefuse block above described.

Having thus described our invention, Wc claim as new and desire tosecure by Letters Patent:

1. In an electrical fuse block, thel combination With a plurality ofcontact clips, of a separating member having a perforation of desi nedshape and size to compel the use of -tuscs designed to lit saidperforations, said member being interposed between said clips.

'2. tion with a plurality of contact clips, of a wall having aperforation of designed shape and size, and a cartridge fuse having anextended member formed and disposed to require insertion within saidperforation t0 permit electrical contact of the fuse terminals with thesaid cli s.

3. In an electrical iuse block, the combination of a base provided withan end opening compartment, suitable clips disposed Within saidcompartment adapted to receive the electrical terminals, a partitionextended across said compartment between said clips having a passage ofdesigned size, a fuse adapted to be inserted Within said com artment andhaving an extended contact a aptlos In an electrical fuse block, thecombinaed to Apass throughv said .passage and as1 1itnames to thisspecification in the presence of able Contact to form electricalconnectronA twosubscribng Witnesses. at the entrance end of saidcompartment,

. ANDREW ALEXANDER MoEEl'rr.

and provlded Wlth an lnsulated handle eX- tended .from theV outer endofl said fuse GEORGE EARL ANDREWS" whereby the same may be inserted andWth- Witnesses:

4drawn from said compartment. v lARTHUR P..JOHNsoN,

In testimony whereof We have signed kour RHODES U, ELDRD;

